Dynamoelectric machine slot wedges



Nov. 14, 1961 w. DRABIK ETAL 3,009,073

DYNAMOELECTRIC MACHINE SLOT WEDGES Original Filed Nov. 15, 1957 Fig 6 Fig 4 Rol/er to App/y Dow/mara' f 22er Flotten/'ng 3|5 Fofcaelo i 2l2f ya 7am The/f Afamey States 6 Claims. (Cl. 310-214) This invention relates to dynamoelectric machines, and particularly, to wedges for closing stator or rotor lamination sots into which conductors or windings have been placed.

This is a divisional application of co-pending application Serial No. 696,822, filed November 15, 1957, now Patent 2,945,140, issued July l2, 1960.

An object of this invention is to provide new and improved electrical-insulating slot wedges for holding motor or generator winding conductors in lamination slots of stators or rotors of dynamoelectric machines.

Another object of this invention is to provide a slot closing wedge having an insulating channel portion, adapted to be inserted transversely across space adjacent to a top portion of a dynamoelectric machine lamination slot provided with lateral undercuts or grooves, and having a central body or metal member which is expanded laterally after insertion within the insulating channel portion for tightly engaging the wedge across the grooves adjacent the top portion of the slot.

Another object of this invention is to provide an expansion-spring slot-closing wedge having an insulating means located laterally on opposite sides of a plurality of loops of a tempered spring member stretched longitudinally to effect lateral contraction of loop ends and released longitudinally to effect lateral expansion of loop ends to contact and resiliently to urge the insulating means into locked engagement with lateral undercuts or grooves provided adjacent to a top portion of each lamination slot of a dynamoelectric machine.

A further object of this invention is to provide a slotclosing wedge for engagement between lateral undercuts or grooves provided adjacent a top space of a lamination slot, the wedge including a channel-type outer insulating member and an inner member of extruded metal with an intermediate portion initially extending upwardly between opposite lateral edges of the extruded metal to be forced flat and expanded laterally effecting engagement of the insulating member against the lateral undercuts of the slot.

Another object of this invention is to provide a slotclosing wedge for maintaining conductors embedded in lamination slots of a dynamoelectric machine stator or rotor, the wedge including an inverted U-shaped insulating-material channel portion into which opposite legs of an inverted Y-shaped body portion of extruded metal are inserted, an upwardly extending leg of the inverted Y- shaped body portion being forced downwardly for flattening the opposite legs of the inverted Y-shaped body portion laterally outwardly positively to engage opposite upwardly extending sides of the channel portion against lateral undercuts or lateral grooves provided adjacent to a top space of each lamination slot into which the wedge is inserted.

Another object of this invention is to provide a slotclosing wedge for maintaining conductors embedded in lamination slots of a dynamoelectric machine stator or rotor, the wedge including a substantially W-shaped body portion of extruded metal to which is bonded an outer peripheral insulating-material portion, the metal body portion being flattened under pressure applied downwardly upon the center of the substantially' W-shaped portion atent ICC thereby laterally expanding the opposite sides of the formerly W-shaped portion and bonded insulating-material portion firmly into locking engagement with lateral undercuts or grooves provided adjacent to a top space of each lamination slot.

Another object of this invention is to provide a method for closing lamination slots using wedges having a central body portion with an initially deformed midsection of metal within an outer insulating portion, including inserting the initially deformed metal midsection and insulation portions between lateral undercuts located adjacent to a space near a top of lamination slots, and expanding the midsection to force the insulating portion and central body portion outwardly and into engagement with each other locking underneath the undercuts.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE l is a fragmentary top view of a longitudinally extended and laterally contracted spring-expansion slot-closing wedge positioned within a top space of a dynamoelectirc machine slot.

FIGURE 2 is a fragmentary top View of the springexpansion wedge of FIGURE 1 in a position where it is longitudinally contracted and expanded laterally for engaging insulating material against undercuts or lateral grooves adjacent to the top space.

FIGURE 3 is an elevational cross-sectional view of the spring-expansion wedge of FIGURE 2 after lateral expansion resiliently locking the wedge into engagement with lateral undercuts adjacent to a top space of a dynamoelectric machine lamination slot shown with winding conductors embedded therein to be retained by the wedge.

FIGURE 4 is a fragmentary elevational cross-sectional perspective View of a modification of a slot-closing wedge in initial extruded shape together with a phantom outline of final laterally-expanded shape 0f the wedge in accordance with the present invention.

FIGURE 5 is a fragmentary elevational cross-sectional perspective view of a slot closing Wedge similar to that represented in FIGURE 4.

FIGURES 6 and 7 are fragmentary elevational crosssectional perspective views of a modified extruded wedge in unexpanded and expanded positions, respectively, in accordance with the present invention.

Slot closing wedges commonly are provided to be forced longitudinally into a space between undercuts or grooves of opposite side surfaces adjacent to a top portion of lamination slots into which winding conductors of a dynamoelectric machine are placed. These conductors are retained firmly in place by such wedges that prevent centrifugal force from effecting displacement of the conductors for example. The wedges generally are driven longitudinally into a top portion of a lamination core slot and a forced fit during this driving action often results in damage which is eliminated in the present invention as Wedges and insulating material are provided over the top of conductors and along opposite side surfaces of the slot having undercuts or grooving for locking engagement by the wedge.

Electrical-insulating slot wedges of the present invention permit use of insulating material to hinder or eliminate stray currents or electromagnetic flux from passing out of `a steel sheet metal or lamination core into metal slot-closing wedges. In FIGURE 1 there is shown one slot-closing wedge in accordance with the present invention. Also shown in FIGURE 1 is a top fragmentary view of a magnetic core generally indicated by numeral 10 and formed of a plurality of laminations 11 stacked in alignment relative to each other for forming a slot generally indicated by numeral 12 and that extends longitudinally of the stack of laminated sheet metal. As illustrated by FIGURES l, 2 and 3, the slot 12 is open at its top and has longitudinal undercuts or grooves 14 provided in opposite side surfaces 1S adjacent to a space near the top portion 12t of each slot 12. Placed in a bottom space portion 12b of each slot below the grooves 14 lare winding conductors (or coils, not shown) 16 which are ernbedded in the slots and surrounded or separated from side and bottom surfaces of each slot by insulating paper 17. Insulating paper 17 can be provided in multiple thicknesses adjacent the top and bot-tom surfaces of the ccnductors 16 of electrically conducting metal that is supplied with electrical energy or current resulting in an electromagnetic ux which is dispersed through the laminated core for use in operation of a motor or generator rotor or stator.

The slot closing wedge illustrated by FIGURES l, 2 and 3 is generally indicated by numeral 18 and includes an insulating-material portion 19 and a central body portion 20. The central body portion Ztl is preferably a metal member which is expanded laterally after insertion in the insulating-material portion 19 both placed in space between grooves 14 of the side surfaces of the slot. As illustrated, the central body portion or metal member is a spring means or sine-waVe-like spring member having a plurality of loops or leg portions Ztix which cross back and forth transversely and progressively relative to the slot extending longitudinally of the stacked laminations 11. Each loop or tnansversely crossing leg portion is joined at opposite ends by bends of curved elbow or end portions Ztie of the spring means. The leg and elbow portions lie in a plane which is substantially lat and parallel to a floor or transverse bottom section 19h of the insulating-material portion 19 which has laterally upwardly extending side wings 19s that are engaged into and locked underneath the grooves 14 of the slot side surfaces. In the cross-sectional view of FIGURE 3, the floor or bottom section 19h of the insulating-material portion is placed and maintained flat adjacent multiple layers of insulating paper 17 over the top of conductors 16 to be retained in the slot 12.

The spring means of the wedge of FIGURES l, 2 and 3 is provided with eyelets or nger grasping portions 22 at opposite ends thereof. By pulling the spring body member 2t) longitudinally at opposite end grasping portions 22, there is effected a temporary longitudinal stretching of the relationship of tnansverse legs 26x relative to end portions 20e as illustrated by FIGURE 1 such that a dimension less than the width of the slot opening is obtained for permitting insertion of the longitudinally extendable spring means downwardly from the top of each slot into space within the insulating-material-portion side wings between grooves or undercuts 14 during lateral contraction of the elbow portions to less than slot Width due to longitudinal expansion or stretching of the spring means. Upon releasing of the ends of the springs in the method of using the wedge illustrated in FIGURES 1, 2 and 3, there is a longitudinal contraction of transverse leg portions 20x and elbow portions Ztle relative to each other back to a natural and resiliently maintained position of the spring means illustrated in FIGURES 2 and 3 for retaining the elbow portions 20e against opposite inner surfaces of side wing portions 19s of the insulating-material portion 19 of the wedge holding the conductors 16 in slot space below the wedge locked in space between undercuts or grooves 14 having surfaces engaged by outer longitudinal surfaces of the side wing portions 19s. In the released natural position of the spring means the elbow portions and transverse leg portions thereof maintain a lateral expanded or extended positioning having a lateral dimension greater than the slot width so as to effect locking engagement of the wedge relative to the slot grooves or undercuts 14. Laterally expanding the body portion of the spring means results in engagement of lateral edges of the insulating material means or side-wing portions relative to the slot undercuts or longitudinal grooves. A plurality of units of lateral contact is provided by elbow portions 29e relative to the insulating material side wings maintained against the longitudinal grooves at opposite side surfaces of the slot. Depending upon stiffness of the insulating-material side wings, a greater or smaller number of units of contact may be required and provided for laterally outward biasing thereof by tempered metal spring means.

In FIGURES 4 and 5 there are shown slightly modied versions of another embodiment of laterally expandable Slot closing wedges 118 and 21; for use in slots 112 `and 212 having top spaces 112i and 212i, respectively, formed by larninations 111 and 211 of cores 110 and 21). Insulating paper 117 and 217 as well as conductors 116 and 216 can be provided comparable to what is shown in FIGURES l, 2, and 3. Comparable insulating-material portions 119 and 21@ having floor segments 119]; and 21% `and side wings 119s and 211s, respectively, are also shown. These insulating-material portions are all substantially U-shaped in cross section and thus are longitudinal channels with upwardly extending sides having outer surfaces to be engaged against undercuts or grooves 114- -and 214, respectively.

The wedges 118 and 218 each have central members or metal body portions 120 and 225, respectively, of extruded metal such as aluminum which is light in weight and therefore advantageous as to effect of centrifugal force for minimizing weight and balancing problems of a dynamoelectric machine armature or rotor for which the wedges of the present invention may be used. Each body portion 120 and 22d has a mid-section or intermediate portion 121 and 221, respectively, which is initially in a deformed position or condition as the body portion is formed of extruded meta-l. Each mid-section is spaced initially extending upwardly relative to the flat oor of the insulating material portion of the wedge. Body portions 12@ and 22@ are in effect inverted Y-shaped members or inner portions `of the wedge of extruded metal havinf7 opposite downwardly extending legs 120x and 229x that terminate in longitudinal extending edges 120e and 223e for engaging side wings 119s and 219s against grooves 114 and 214, respectively. Upwardly extending legs 122 and 222 of body portions 126 and 220, respectively, serve as cooling or heat radiating tins to dissipate heat from the extruded metal and also serve as an upwardly extending projection to be rolled at and downwardly as outlined by a phantom representation of a roller 222r used to apply force progressively along a peripheral upper edge of the tin. A solid downwardly stamping force applied simultaneously along the longitudinal length of the n can also be used.

Application of force to legs 122 and 222 results in a flattening of mid-sections 121 and 221, respectively, concurrent With laterally expanding o-f legs 122%: and 220x for engaging edges 12tlg and 223e firmly against side wings `119s and 219s. The version of FIGURE 4 uses a V-shaped structure as formed by legs 129x and the version of FIGURE 5 uses a trough or cup-like U-shaped structure as formed by legs 220x. Arrows in FIGURE 5 illustrate lateral expansion and spreading of the legs 220x resulting from downward force applied to leg or iin 222. Phantom representations of resulting inverted T-shaped wedges also are shown in the views of FIGURES 4 and 5.

Another version of laterally expandable slot-closing wedges in accordance with the present invention is shown in FIGURES 6 and 7 wherein reference numerals 310, 311, 312, 314, 315, etc., are applied to laminated-core slot structure similar to that identified by numerals 216, 211, 212, 214, 215, etc., in FIGURE 5, for example. Wedge 318 of FIGURES 6 and 7 includes a central member o-r body portion 3255 of extruded metal initially having a substantially W-shaped cross section shown by FIGURE 6. A mid-section or intermediate portion 321 of the central member is provided extending upwardly in spaced relation t0 at insulating paper 317 over conductors 3l6 in slot 312. Insulating material portion 319 is bonded to a lower peripheral surface of central member 3420 and is preferably made of polyetser glass.

FIGURE 7 illustrates how mid-section 3-241 is flattened to mid-section 321f through force applied downwardly thereto to effect lateral expanding of legs or segments 320x that results in engaging edges 320e and side wing edges 3419s of the insulating-material portion 319 to a position complementary to and between grooves 314. Channel-type instead of bonded polyester-glass type insulating material can also be used. The wedge of FIG- URES 6 and 7, like the wedges of FIGURES 4 and 5, is preferably of extruded light-weight metal.

While the embodiments of the present invention as herein disclosed constitute a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A wedge for closing a dynamoelectric machine lamination slot into which winding conductors have been placed to be retained therein below opposite side undercuts of the slot engaged by the wedge, comprising, a channel-type outer insulating member, and an inner longitudinally continuous body of unitary extruded metal having a fully integral intermediate portion downwardly deformable to be positioned solidly and intermediately fully between opposite lateral edges of t-he unitary extruded metal to be forced hat for laterally expanding said inner body and thereby effecting transverse engagement of said insulating member positively against the lateral undercuts of the slot so as to have said longitudinally continuous body of unitary extruded metal to hold both said insulating member and the conductors rmly within the slot.

2. A wedge for closing a dynamoelectric machine lamination slot into which winding conductors have been placed to be retained therein below a space between opposite side grooves that extend longitudinally of the slot and are engaged by opposite lateral edges of the wedge, comprising, a channel-type outer insulating member, and an inner inverted Y-shaped lbody of extruded metal having opposite downwardly extending legs inserted into the insulating member adjacent to the top of the slot, said Y-shaped body having one leg extending upwardly out of the top of the slot along 'which force is applied to atten and laterally spread said opposite downwardly extending legs against lateral edges of said insulating member thereby securely locking said wedge between the side grooves to hold the conductors firmly in each slot.

3. A slot-closing wedge for maintaining conductors embedded in lamination slots of a dynamoelectric Inachine stator or rotor, comprising, a substantially W-shaped body portion of extruded metal, and an outer insulatingmaterial portion bonded to a lower periphery of said W- shaped body portion, said metal body portion being ilattened under pressure applied downwardly upon the center of the substantially W-shaped portion thereby laterally expanding the opposite sides of the formerly W-shaped portion and bonded insulating-material portion firmly into locking engagement with lateral undercuts provided adjacent to a top space of each lamination slot.

4. The wedge of claim l in -which said inner body is made of extruded aluminum which is light in weight and which has an upwardly extending cooling n attached integral with said intermediate initially upwardly extending portion, said fin transmitting pressure applied along a top longitudinal edge thereof for flattering and laterally expanding said intermediate portion.

5. The wedge of claim l wherein said longitudinally continuous body of unitary extruded metal has an inverted Y-shaped cross-section deformable to a T-shape to provide an upwardly extending cooling lin integrally therewith.

6. The wedge of claim l wherein said longitudinally continuous body of unitary extruded metal has a W- shaped cross-section deformable to a shallow U-shape.

References Cited in the file of this patent UNITED STATES PATENTS 880,429 Treat Feb. 25, 1908 1,260,674 Jackson Mar. 26, 1918 FoRErGN PATENTS 245,805 Germany Apr. 18, 1912 

